Internal combustion engines, in the process of operation, experience engine wear and fouling with engine deposits overtime. As the engine continues in operation and with the use of hydrocarbon fuels, there is a build up of thermal oxide derived varnish like/lacquer deposits on the surfaces of the combustion chamber and components. The piston is typically the most highly stressed part of the engine, getting deposits on the surface and in the grooves, resulting in piston ring sticking, piston scuffing, and ring and cylinder wear. There are various industry and manufacturers standards and methods governing the deposit formation of automotive engine oils and the classification and quantification of lacquer and carbon deposits, e.g., to rate an engine oil, a test piston which has been subjected to many hours of operation in a running engine is rated. The Coordinating Research Counsel (CRC) has developed a standard rating scale for lacquer and carbon deposits on engine parts. Lubricant efficacy can be measured, in part, by classifying and measuring the amount of lacquer and carbon deposited on its surface and in the ring grooves in terms of color, thickness, hardness, etc. In one rating method, deposits are evaluated by volume and appearance, ranging from 10 (clean absence of deposits) to 0 (maximum deposits).
Various instruments and devices have been proposed to carry out the piston deposit rating job. U.S. Pat. No. 5,118,194 discloses an optical inspection system with sensors, a video imaging system and means to process the digital presentation of the deposits. However, rating is not as easy as matching the closest shade of color. There are different parts to rate, e.g., pistons, gears, oil pans, etc.) as well as different types of engines. Rating is ideally done in a laboratory setting under controlled conditions of light and temperature to ensure uniformity. However, this is not always the case there are needs to field rating of equipment parts in remote locations, e.g., a mine, an ocean freighter, etc.
As optoelectronic solutions are not yet fully developed and practical, deposit rating is still most reliably done by human raters. Most raters follow a breakdown examination method in which the part, e.g., a piston, is broken down or divided into sections for careful examination of each individual section.
The invention relates to a device for use in rating engine deposits, allowing engine raters to divide an engine part, e.g., a piston, into sections for examination/rating with minimal disruption to the fragile deposits on the part. The device also allows raters to rate pistons of various sizes/types, e.g., from small pistons for use in weed whackers to large-sized pistons for use in locomotives, with the use of an adjustable rating device.